This invention relates to a data transmission method and a data transmission apparatus for use in transmitting video data, audio data and metadata other than the video data and the audio data, or the like.
The SDI (Serial Digital Interface) format is standardized by SMPTE-259M of the SMPTE (Society of Motion Picture and Television Engineers) which issues standards concerning television engineering and video engineering. This SDI format is fundamentally a signal standard for the D-1 format or the D-2 format which may be a digital signal standard.
This SDI format is able to effect the transmission for only data of limited media. To be concrete, media that can be transmitted may be one channel of video data and about 8 channels of baseband audio data. For this reason, the SDI format is unsuitable for multimedia or multichannel.
Also, the SDTI (Serial Data Transport Interface) format is standardized by SMPTE-305M of the SMPTE. This SDTI format is suitable for multimedia or multichannel while the advantage of the SDI format is being effectively utilized and a common property with the SDI format is being kept in part. This SDTI format is the standard for transmitting the baseband signal and is able to transmit an end synchronizing code (EAV: End of Active Video) an a start synchronizing code (SAV: Start of Active Video) together.
That is, according to the SDTI format, there can be transmitted a serial digital transfer interface transmission packet in which an interval of each line of a video frame comprises an area into which an EAV is inserted, an ancillary data area into which ancillary data is inserted (ancillary data portion ANC), an area into which an SAV is inserted and a payload area into which video data and audio data are inserted.
It is considered that the transmission of the stream (SDTI stream) based on such SDTI format may be utilized in the VTR editing. In the VTR editing, the SDTI stream may be transmitted from a reproducing VTR side to a recording VTR side.
Since VTRs may use a servo motor as a tape driving system or the like and cannot be immediately operated at the editing point, for the purpose of synchronization of a servo or the like, they need a pre-roll (pre-roll) interval which may be a runup interval for a preparation of some degree before IN (In)-point of editing. Similarly, since VTRs cannot stop a tape driving system or the like immediately, they need a post-roll (post-roll) interval after OUT (Out)-point of editing.
Therefore, in the above-mentioned VTR editing, the stream transmitted from the reproducing VTR side to the recording VTR side should have stream information indicative of whether a picture unit belongs to the pre-roll interval located ahead of the editing interval, whether a picture unit belongs to the editing interval and whether a picture unit belongs to the post-roll interval located behind the editing interval.
An object of this invention is to make the VTR editing become possible in which a stream may be transmitted from a reproducing VTR side, for example, to a recording VTR side.
A data transmission method according to this invention is a data transmission method for transmitting a serial digital transfer interface transmission packet in which an interval of each line of a video frame comprises an end synchronizing code area into which an end synchronizing code is inserted, an ancillary data area into which ancillary data is inserted, a start synchronizing code area into which a start synchronizing code is inserted and a payload area into which main data comprising video data and/or audio data is inserted. This data transmission method comprises a first step of inserting first data containing extension data having stream information indicating whether or not a picture unit belongs to a pre-roll interval located ahead of an editing interval, whether or not a picture unit belongs to an editing interval and whether or not a picture unit belongs to a post-roll interval located behind an editing interval and second data containing the main data into the payload area at the picture unit of the video data and a second step of transmitting the transmission packet in which the first data and the second data are inserted into the payload area in the form of serial data.
For example, the stream information indicating that the picture unit belongs to the editing interval further indicates whether or not the picture unit is the first picture unit of the editing interval, whether or not the intermediate picture unit of the editing interval, whether or not the picture unit is the last picture unit of the editing interval and whether or not the picture unit is the first and last picture units of the editing interval.
Also, a data transmission apparatus according to this invention is a data transmission apparatus for transmitting a serial digital transfer interface transmission packet in which an interval of each line of a video frame comprises an end synchronizing code area into which an end synchronizing code is inserted, an ancillary data area into which ancillary data is inserted, a start synchronizing code area into which a start synchronizing code is inserted and a payload area into which main data comprising video data and/or audio data is inserted. This data transmission apparatus includes a means for inserting first data containing extension data having stream information indicating whether or not the picture unit belongs to a pre-roll interval located ahead of an editing interval, whether or not the picture unit belongs to the editing interval and whether or not the picture unit belongs to a post-roll interval located behind the editing interval and second data containing the main data into the payload area at the picture unit of video data and a means for transmitting the transmission packet in which the first data and the second data were inserted into the payload area in the form of serial data.
According to this invention, the first data containing the extension data having the stream information and the second data containing the main data comprising the video data and/or audio data are inserted into the payload area. Therefore, since the receiving side is able to control an operation of a tape driving system of a recording VTR, for example, a VTR editing becomes possible.
A data reception method according to this invention is a data reception method of receiving a serial digital transfer interface transmission packet in which an interval of each line of a video frame comprises an end synchronizing code area into which an end synchronizing code is inserted, an ancillary data area into which ancillary data is inserted, a start synchronizing code area into which a start synchronizing code is inserted and a payload area into which first data containing main data comprising video data and/or audio data and second data containing extension data having stream information indicating whether or not a picture unit belongs to a pre-roll interval located ahead of an editing interval, whether or not a picture unit belongs to an editing interval and whether or not a picture unit belongs to a post-roll interval located behind an editing interval are inserted at the picture unit of video data. This data reception method comprises the steps of a first step of receiving a transmission packet, a second step of extracting main data and extension data from the received transmission packet and a third step of controlling recording of main data on the basis of stream information within the extracted extension data.
Also, a data reception apparatus according to this invention is a data reception apparatus for receiving a transmission packet in which an interval of each line of a video frame comprises an end synchronizing code area into which an end synchronizing code is inserted, an ancillary data area into which ancillary data is inserted, a start synchronizing code area into which a start synchronizing code is inserted and a payload area into which first data containing main data comprising video data and/or audio data and second data containing extension data having stream information indicating whether or not a picture unit belongs to a pre-roll interval located ahead of an editing interval, whether or not a picture unit belongs to an editing interval and whether or not a picture unit belongs to a post-roll interval located behind an editing interval are inserted at the picture unit of video data. This data reception apparatus includes a means for receiving a transmission packet, a means for extracting main data and extension data from the received transmission packet and a means for controlling recording of main data on the basis of stream information within the extension data.
According to this invention, the extension data having the stream information and the main data comprising the video data and/or audio data are extracted from the received transmission packet at the picture unit of the video data, and the recording of the main data is controlled on the basis of the stream information. An operation of a tape driving system or the like of a VTR is started in the pre-roll interval, for example, a synchronization of a servo or the like is established, the main data is recorded during the editing interval, and the operation of the tape driving system or the like of the VTR is stopped during the following post-roll interval. Thus, a VTR becomes possible.